Structure-Function Relations in the Leaves of Maize and Barley: Sink-to-Source Conversion

9320218 Evert所提出的研究涉及利用明场、透射电子、落射荧光和共聚焦激光扫描显微镜对玉米和大麦叶片的发育和结构的研究。 在此基础上，还将进行以下实验研究：（1）源叶和库叶中光合同化物的途径;（2）源叶和库叶韧皮部的装载和卸载部位和机制;（3）库-源转换过程中的结构变化;（4）水分通过蒸腾流进入叶片，进入不同层次的中脉、小脉和横脉的途径。 玉米和大麦，作为其他禾本科植物的叶子，提供了一个极好的系统，以下一系列的细胞和亚细胞的事件，正是因为极化细胞分裂的基础上的叶的结果在一个不混合的梯度细胞发展。 同样的系统应该是确定汇到源转换的潜在机制的理想选择。 玉米和大麦的叶子在结构和发育上都有许多细节上的不同。 这两个经济上重要的草的叶子的平行研究将提供一个更平衡的图片的结构-功能关系的草叶子比只调查其中之一。 这些研究的结果将对作物生产力具有长期的实际意义，并对病毒、昆虫、支原体和其他寄生虫与其宿主的关系以及杀虫剂和生长调节物质在栽培植物中的运动感兴趣的研究人员具有价值。 ***

9320218 Evert The proposed research involves studies on the development and structure of the leaves of maize and barley, utilizing bright- field, transmission electron, epifluorescence, and confocal laser scanning microscopy. The developmental and structural studies will be complemented by experimental studies aimed at determining: 1) the pathways followed by photoassimilates in source and sink leaves; 2) the sites and mechanisms of phloem loading and unloading in source and sink leaves, respectively; 3) the structural modifications associated with the sink-to-source conversion; and 4) the pathways followed by water, which enters the leaf in the transpiration stream, to intermediate, small, and transverse veins at various levels of leaves undergoing sink-to-source conversion. Maize and barley, as other grass leaves, provide an excellent system for following a sequence of cellular and subcellular events precisely because polarized cell division at the base of the leaf results in an unmixed gradient of cell development. This same system should be ideal for determining the underlying mechanisms of the sink-to-source transition. The leaves of maize and barley differ in many details both structurally and developmentally. Parallel studies on the leaves of both of these economically important grasses will provide a more balanced picture of structure-function relations in grass leaves than would an investigation of only one of them. The results of these studies will have long-term practical importance in relation to crop productivity and will be of value to investigators interested in relations of viruses, insects, mycoplasmas, and other parasites to their hosts and in the movement of insecticides and growth regulating substances in cultivated plants. ***